1. Technical Field
The present invention relates to an image processing device, a projector, and an image processing method.
2. Related Art
In the field of image processing devices, there has been known a technology of extending the range of the distribution of the luminance of image data to thereby improve the contrast of the image. In JP-A-2007-41535 (Document 1), there is described the fact that in calculating the extension coefficient for extending the range of the luminance distribution, the extension coefficient is calculated using the maximum value and an average value of the luminance of pixels included in a small area in the central, area of the image in order to reduce an influence of a black bar for subtitles or black bars corresponding to the aspect ratio. In JP-A-2008-225026 (Document 2), there is described the fact that in the case of extending a video signal on which an OSD (On Screen Display) signal is superimposed, the luminance of the OSD signal is previously set to a value smaller than the maximum value of the luminance of the video signal to thereby suppress degradation of the image quality of the OSD.
In the case in which the OSD is displayed while being superimposed on the image (hereinafter referred to as a “main image”) corresponding to the video signal, it is not necessarily desirable for the OSD to be displayed in the central area of the main image. For example, in the case in which important information displayed by the main image exists in the central area of the main image, the OSD is displayed in an area other than the central area of the main image in some cases. In this case, in the technology described in Document 1, since the luminance of the OSD signal is not considered in calculating the extension coefficient, there is a possibility of causing the highlight detail loss in which most of the pixels included in the OSD are whitened. Further, in the technology described in Document 2, there is a problem that there occurs a restriction in designing the OSD.